Doctors today employ one or more heart signal machines to make a determination of one or more fetal heart component signals. The heart signal machine obtains heart signal information from a pregnant mother. The heart signal machine in one example comprises one or more processor components. The heart signal machine employs the processor components to make a determination of the fetal heart component signal based on the heart signal information.
In one example, the heart signal machine comprises an ultrasound machine. The ultrasound machine in one example allows the doctor to view heart muscle movement of the fetus. For example, the doctor infers the fetal heart component signal from the heart muscle movement. One shortcoming of an employment of the ultrasound machine to infer the fetal heart component signal is that the heart component signal is not a measurement of the electrical activity of fetal heart muscle movement. For example, the doctor could only diagnose major defects of the fetal heart through employment of the ultrasound machine.
In another example, the heart signal machine comprises a magnetocardiogram (“MCA”) machine and the heart signal information comprises magnetic heart signal information. The magnetocardiogram machine in one example employs one or more magnets to obtain the magnetic heart signal information from the pregnant mother. The processor component of the magnetocardiogram machine employs the magnetic heart signal information to make a determination of the fetal heart component signal. One shortcoming of an employment of the magnetocardiogram machine to make the determination of the fetal heart component signal is that the magnetocardiogram machine is expensive.
In yet another example, the heart signal machine comprises an electrocardiogram (“ECG”) machine and the heart signal information comprise electrical heart signal information. The electrocardiogram machine in one example employs one or more electrodes to obtain the electrical heart signal information from the pregnant mother. Diagnostic information can best be obtained from a fetal electrocardiogram. However access to that fetal electrocardiogram in a noninvasive manner is not available early in the pregnancy. The fetus' electrocardiogram is extremely weak early in the pregnancy. Not only is the fetus' electrocardiogram extremely weak in relation to the maternal electrocardiogram in which it is embedded, but it is also weak in relation to the various noises picked up by the electrocardiogram electrodes. The noises are partly due to electromyographic (“EMG”) activity picked up by these electrodes, especially when the electrodes are placed on the mother's abdomen or lower back.
The processor component of the electrocardiogram machine in one example employs independent component analysis (“ICA”) to separate the fetal electrical heart component signal from the electrical heart signal information. One shortcoming of an employment of the electrocardiogram machine to determine the fetal electrical heart component signal is that the fetal electrical heart component signal can have an amplitude that is 1/2,000 of the amplitude of a maternal electrical heart component signal in the 12th to 15th week of pregnancy. Furthermore, the electrocardiogram machine cannot separate very weak fetal heart signals, such as fetal heart signals early in the pregnancy at the 12th to 25th gestation week. The fetal electrical heart component signal in one example is embedded in noise that has a greater amplitude than the fetal electrical heart component signal. Thus, the noise makes it difficult to accurately determine the fetal electrical heart component signal in a noninvasive manner. The electrocardiogram machine alone cannot separate a major portion of the noise component signal from the fetal electrical heart component signal. Thus, the doctor is unable to diagnose one or more fetal heart defects early enough into the pregnancy to treat the fetal heart defects.
The fetal electrocardiogram separation problem is complicated by the fact that the noise in each electrocardiogram recording channel is different from that in the other channels. Classic singular value decomposition type (including independent component analysis based) separation methods must assume that the number of incoming signals (channels) is smaller or equal to the number of uncorrelated or independent sources that form the incoming sources. However, this is not the case in the fetal electrocardiogram separation problem due to the different statistics of the noises in the various channels. Hence, if there were one noise common to all electrodes in a three channel situation, then the number of source signals considered in the fetal electrocardiogram separation problem would have been three, namely, fetal electrocardiogram, maternal electrocardiogram, and noise. However, in reality there are five sources in the three channel fetal electrocardiogram separation problem. The five sources are the fetal electrocardiogram, the maternal electrocardiogram, and three noises of different statistics. For example, each channel has a separate noise signal. This mixture cannot be separated by classical separation algorithms of any type unless all three noises are of considerably lower signal-power than the fetal electrocardiogram signal power. However, early in a pregnancy, the three noises are not of considerably lower signal-power than the fetal electrocardiogram signal power.
Thus, a need exists for a heart signal machine that can separate a fetal heart component signal from heart signal information obtained from a pregnant female.